The ink jet process is known (cf. for example the chapter, "Ink jet printing" by R. W. Kenyon in Chemistry & Technology of Printing & Imaging Systems, editor Peter Gregory, Blackie Academic & Professional, Chapman & Hall, 1996, pp. 113-138, and the literature cited therein).
In this process, ink jet images are produced by spraying a fine, imagewise modulated jet of a dye solution or dispersion onto a recording material. Better quality recording materials have an image-receiving layer on a support material, the layer containing an agent intended to bind the ink jet dye in a spread- and smudge-resistant manner. DP 609 930 accordingly discloses the provision of an ink receiving layer on the support, the layer containing at least one mordant which is a polymer or copolymer having a phosphonium group. The stated document gives a comprehensive description of the prior art relating to ink jet materials. The results achieved hitherto are, however, not adequate.